Guards against errors that are hard to track down:

- if crt0s is empty (eg. because crt0-y is still used),
  break the build, and say where that behaviour changed
- if a stage is unusable for cbfstool because it's placed
  outside the ROM space (linked to 0 is somewhat notorious),
  warn about it, give some hints and exit instead of crashing.

Signed-off-by: Patrick Georgi <patrick.georgi@coresystems.de>
Acked-by: Stefan Reinauer <stefan.reinauer@coresystems.de>


git-svn-id: svn://svn.coreboot.org/coreboot/trunk@5077 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1

util/cbfstool/cbfs-mkstage.c

@@ -126,6 +126,11 @@ int parse_elf_to_stage(unsigned char *input, unsigned char **output,
 		data_start = *location;
 	}
 
+	if (data_end <= data_start) {
+		fprintf(stderr, "E: data ends before it starts. Make sure the ELF file is correct and resides in ROM space.\n");
+		exit(1);
+	}
+
 	/* allocate an intermediate buffer for the data */
 	buffer = calloc(data_end - data_start, 1);